The World Social Forum (WSF) is an annual meeting, based in Brazil, that defines itself as "an opened space – plural, diverse, non-governmental and non-partisan – that stimulates the decentralized debate, reflection, proposals building, experiences exchange and alliances among movements and organizations engaged in concrete actions towards a more solidary, democratic and fair world....a permanent space and process to build alternatives to neoliberalism". It is held by members of the alter-globalization movement (also referred to as the global justice movement) who come together to coordinate world campaigns, share and refine organizing strategies, and inform each other about movements from around the world and their issues. It tends to meet in January at the same time as its "great capitalist rival", the World Economic Forum's meeting in Davos, Switzerland. This date is usually picked in hopes that having a meeting that promotes alternative answers to world economic problems opposite the World Economic Forum will help the WSF's ideas get better coverage in the news media.
Originated by Oded Grajew, the first WSF was held from 25 January to 30 January 2001 in Porto Alegre, Brazil, organized by many groups including the French Association for the Taxation of Financial Transactions for the Aid of Citizens (ATTAC). The WSF was sponsored, in part, by the Porto Alegre government, led by the Brazilian Worker's Party (PT). The town was experimenting with an innovative model for local government which combined the traditional representative institutions with the participation of open assemblies of the people. 12,000 people attended from around the world. At the time, Brasil was also in a moment of transformation that later would lead to the electoral victory of the PT candidate Luiz Inácio Lula da Silva.
The third WSF was again held in Porto Alegre, in January 2003. There were many parallel workshops, including, for example the Life After Capitalism workshop, which proposed focussed discussion on non-communist, non-capitalist, participative possibilities for different aspects of social, political, economic, communication structures. Among the speakers was American linguist and political activist Noam Chomsky.
The fourth WSF was held in Mumbai, India, from 16 January to 21 January 2004. The attendance was expected to be 75,000 and it shot over by thousands. The cultural diversity was one notable aspect of the forum. A notable decision that was taken was the stand on Free Software. One of the key speakers at the WSF 2004 was Joseph Stiglitz.
The fifth World Social Forum for 2005 was held in Porto Alegre, Brazil between 26 January and 31 January. There were 155,000 registered participants at the Forum, with most coming from Brazil, Argentina, the United States, Uruguay, and France. A number of participants in the forum released the Porto Alegre Manifesto.
The sixth World Social Forum was "polycentric", held in January 2006 in Caracas (Venezuela) and Bamako (Mali), and in March 2006, in Karachi (Pakistan). The Forum in Pakistan was delayed to March because of the Kashmir earthquake that had recently occurred in the area.
The seventh World Social Forum was held in Nairobi, Kenya in January 2007. There were 66,000 registered attendees, and 1,400 participating organizations from 110 countries, making it the most globally representative WSF so far. It was criticized as being 'an NGO fair'and movements of the poor in Kenya and South Africa mounted vigorous protests against some of the NGOs that attended and, in their view, dominated the forum in the name of the African poor.
The eighth World Social Forum in 2008 was not organized at a particular place, but globally, which means by thousands of autonomous local organizations, on or around January 26. They are also known as the Global Call for Action. The ninth World Social Forum took place in the Brazilian city of Belém, located in the Amazon rainforest, between January 27 and February 1, 2009.
Since 2001, the United Nations has had a presence at the WSF through UNESCO, showing the institutional credibility achieved by the forum, seen by UNESCO as a "prime opportunity for dialogue and a laboratory of ideas for the renewal of public policies" through "critical reflection on the future of societies we want to create and for elaborating proposals in search of solidarity, justice, peace and human rights".
The WSF has prompted the organizing of many regional social forums, including the Americas Social Forum, European Social Forum, the Asian Social Forum, the Mediterranean Social Forum and the Southern Africa Social Forum. There are also many local and national social forums, such as the Italian Social Forum, India Social Forum, Liverpool Social Forum and the Boston Social Forum. The first-ever United States Social Forum took place in Atlanta in June 2007. Regional forums have taken place in the Southwest Northwest, Northeast, Midwest and Southeastregions of the United States.
Most, though not all, social forums adhere to the WSF Charter of Principles drawn up by the World Social Forum.
This mural in Seattle's Chinatown echoes the slogan of the World Social Forum: 'Another world is possible'.
The WSF has, especially in recent years, been strongly criticised for replacing popular movements of the poor with NGOs. Movements of the poor in poorer parts of the world, like Africa, have argued that they are almost completely excluded from the forum and in countries like Kenya and South Africa they have protested against donor funded NGOs that, they argue, determine and dominate African representation at the forum. It has also been argued that NGOs sometimes compete with popular grassroots movements for access to the forum and for influence there.
The WSF has also been criticized, particularly by socialist and communist left parties, for producing few practical ideas, concentrating instead on general and vague criticisms of neoliberalism and imperialism. On the other hand some, particularly anarchists, have criticised the WSF for attempting to act as a central decision making location for dissident groups, as the Communist Internationals once did. Most WSF participants would counter that the WSF is not a decision-making body, but rather a space for public deliberation. A far more prevalent criticism runs in the opposite direction: that the group has no established procedure for adopting consensus statements or advocacies.
Right-wing opponents of the current global order have criticized the supposed pluralism of the WSF, as it only includes movements on the left (from social democrats to anarchists).
Some activities by activists attending the WSF have also been criticised, such as in the WSF 2001, where activists invaded and destroyed a plantation of experimental transgenics of the Monsanto Company enterprise.
- Mark Butler (2007), "[re]connecting the World Social Forum"
- Jose Correa Leite (2005), The World Social Forum: Strategies of Resistance, Haymarket Books 
- Jackie Smith. (2004). The World Social Forum and the challenges of global democracy. Global Networks. 4(4):413-421.
- T. Teivainen. (2002). The World Social Forum and global democratisation: learning from Porto Alegre. Third World Quarterly. 23(4):621-632.
- William F. Fisher and Thomas Ponniah (2003). Another World is Possible: Popular Alternatives to Globalization at the World Social Forum
- Boaventura de Sousa Santos (2005). O Fórum Social Mundial: manual de uso, Cortez Editora.
- Sen, Jai, Anita Anand, Arturo Escobar & Peter Waterman (eds). 2004. The World Social Forum: Challenging Empires. New Delhi: The Viveka Foundation.